From Clomosy Docs
procedure CloseFile(var FileHandle TextFile);
The CloseFile procedure closes an open file. The file must be assigned and opened with Insert, Reset, or Rewrite. The file is closed and the handle is made available for further assignment to the files.
Example
var
myFile : TextFile;
{
// Try to open the Test.txt file for writing to
AssignFile(myFile, 'Test.txt');
ReWrite(myFile);
// Write a couple of well known words to this file
WriteLn(myFile, 'Hello');
WriteLn(myFile, 'World');
// Close the file
CloseFile(myFile);
// Reopen to append a final line to the file
Append(myFile);
// Write this final line
WriteLn(myFile, 'Final line added');
// Close the file
CloseFile(myFile);
// Reopen the file for reading
Reset(myFile);
// Display the file contents
while (not Eof(myFile))
ReadLn(myFile);
// Close the file for the last time
CloseFile(myFile);
}